DC to DC converters change DC electrical power from one voltage level to another. Examples include stepping 24 volts DC from a truck battery down to 12 volts DC for a car radio, stepping 5 volts DC on a computer mother board down to a lower DC voltage for an integrated circuit, and stepping 1.5 volts DC from a battery up to a higher voltage to operate electronic circuitry. DC to DC converters also may be used to provide noise isolation, power bus regulation, etc. Naturally, it is desired for this conversion of voltages to be efficient. Energy consumed by the circuitry and components of the converter have a negative impact on this efficiency.
There are various types of DC to DC converters including the “buck”, “boost”, “buck-boost”, and “Cuk”. While the “buck” and “boost”. step the voltage down and up, respectively, the “buck-boost” and “Cuk” may step the voltage in either direction.
Many improvements have been made to these DC to DC converters in recent years with improved conversion efficiency and reduced size. However, an increasing demand for reduced size electronic signal processing equipment requires smaller size and less weight of electronic power processing equipment. This results in increased switching frequency at which DC to DC switching converters operate and therefore, proportionally increased switching power losses.
One version of the “Cuk” converter described in U.S. Pat. No. 6,388,896, includes a lossless DC to DC converter having high efficiency and elimination of switching losses enabling a high switching frequency with reduction of converter size and weight. While this “Cuk” converter describes a timing sequence for signals to switch transistors disclosed therein, there is no mention of the timing control circuit used to generate these signals.
Accordingly, it is desirable to provide a timing control circuit for a DC to DC power converter having lossless switching. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.